Rifamycin b derivatives and method of producing same



United States Patent 3,313,804 RIFAMYCIN B DERIVATIVES AND METHOD OF PRODUCING SAME Plem sens i p g M i i g asslgnors to 5 heating rifamycin B with the ammonia or amine at the No Drawing. eplieitllzd Ithy-,8, 2 Z Y 279,003 Boiling point of the solvent in a period of time varying Claims priority, application Great Britain, May 25 1962, etween 15 minutes and 2 hours, according to the desired 20,255; rifamycin-amide.

11 Cl i (C1, 260 239,3) After concentrating the solvent and on cooling the dicyclohexylurea so obtained (scarcely soluble in tetrahy- The present invention is concerned with new antibiotic drofuran) crystallizes out. substances and the process for preparing the same. In The concentrated solution is then generally diluted with our US. co-pending application 12,654, filed March 4, water acidified with hydrochloric or sulphuric acid and 1960, which issued as Patent No. 3,150,046 on Sept. 22, extracted with a water-insoluble solvent, such as benzene. 1964, we described the preparation of the antibiotic rifa- 15 The solvent is concentrated to a small volume and by mycin by fermentation of a strain of Strep yces medithe addition of a solvent miscible with the solvent used terranei ATCC 13685. As described in the above applifor extraction and in which the reaction product is not cation, rifamycin is a mixture of highly active antibiotic soluble, such as petroleum ether when benzene was used substances. for extraction, the rifamycinamide precipitates. The

Rifamycin B is one of these substances, it has the proamides are then recrystallized, if necessary, from an posed empirical formula C H N0 it is a dibasic acid appropriate solvent.

(pH /2=2.8; pH /2=6.7) and one of the two acidic The amides of rifamycin B are yellow-orange colored functions was found to be a carboxyl group. substances which generally can be crystallized very easily.

One of the particular properties of rifamycinB is its They have no well-defined melting points and they deactivation in aqueous solution i.e. its conversion into compose with darkening above about 250 C. They are another substance possessing a still higher degree of antisoluble in methanol, ethanol, benzene, acetone, ethyl acebacterial activity. tate, very scarcely soluble in water and petroleum ether.

The activation product, called by us rifamycin S, has They show an acidic function which is not a carboxyl the empirical formula C37H47NO12 and by mild reduction with pH /2 varying between 3.0 and 4.0 and therefore can be converted into rifamycin SV (C37H49NO12), anform neutral salts with organic and inorganic bases. other new antibiotic of the rifamycin family. Both rifa- The sodium salt of the amides of rifamycin B are fairly mycin S and rifamycin SV lack the carboxyl group which soluble in water at a neutral pH. All the prepared amides during the so-called activation is removed in the form of show in the U.V. and in the visible region of the spectrum glycolic acid. bands similar to those of rifamycin B, with maximum New derivatives of rifamycin B have now been preat 220-225 m 304-305 mg and 424-430 my. in a buffer pared wherein the carboxyl group (the removal of which solution at pH 7.3. The specific absorptions in rifamycins S and SV considerably increases their antibiotic activity) is blocked by conversion into simple, pril'lm. mary and secondary amides.

The process for preparing the amides of rifamycin B 40 are lower than those of rifamycin B increasing proporconsists in reacting rifamycin B with primary and secondtionally With the molecular Weight 3 Show a Considary amines or ammonia in the presence of dehydrating erable antibiotic activity against gram-positive bacteria agents such as carbodiimides. In most cases dicycloand against Mywbacterillm' tuberculosishexylcarbodiimide was used as the condensing agent and In the fOlIOWing table the minimal inhibitory Concentetrahydrofuran was used as the solvent. trations of a number of amides against gram-positive The condensation of rifamycin B and the primary and and gram-negative bacteria and Mycobacterium tubercusecondary amines in tetrahydrofuran and in the presence losis are given.

TABLE of dicycl-ohexylcarbodiimide occurs also at room temperature; however, under these conditions a period of several hours is necessary for completion of the reaction.

The reaction is therefore preferably carried out by Rilamycin B amide with Minimum inhibitory concentrations, 'yiml.

M. aureus S. faec. S. haemol. B. subtilis Proteus coli Klehs. Pseud. H37 RV pneumon. aer.

Ammonia 1. 5 9. 2 0. 18 12. 5 200 200 200 200 0. 009 Monomethylami 0. 16 1 6. 2 0. 06 200 200 200 200 0. 15 Monoethylamine 0.08 0. 5 0.025 3. 1 200 150 200 200 0. 15 Monoisopropylamineu 0. 16 1 0.06 3. 1 200 200 200 200 0. 075 Dimethylamine 0. 06 0.75 0. 01 1. 5 100 100 100 (0. 04) (0. 3) (0. 037) (1. 5) (100) (25) (25) (100) (0. 018) Diethylamine 0. 01 0. 08 0. 0075 0. 6. 2 25 25 50 0. 075 5-hydr0xypent ylamine 0.2 1. 2 0. 18 3. 1 200 200 200 200 0. 1 Pyrr0lidine 0. 045 0. 37 0. 005 1. 5 50 25 25 50 0. 01 Piperidine. 0. 0075 0. 1 0. 005 0. 75 25 6. 2 25 25 0. 005 Morphollne 0. 3 1. 2 0. 045 1. 5 200 50 50 200 0. l l-methylpiperazine- 0. 09 1. 5 O. 045 3. 1 200 50 50 Dimethylazetidine 0. 045 0. 2 0.02 0.75 100 50 50 100 0. 075 4-torrnyl--phenylpiperazine. 0. 23 2. 3 0. 09 6. 2 200 200 200 200 0. 037 4,4 dibutyl-pyrazolidinen- 0. 18 1. 5 0. 035 6. 2 200 200 200 200 0. 01 n 'no 0. 1 0. 75 0. 12 3. 1 200 200 200 200 O. ()1 p-Chloroanilme. a 0. 25 0. 35 0. 12 2 200 200 200 200 0. 15 p-Br0rn0an1line 0. 3 0. 25 0. 2 1. 5 200 200 200 200 0. 005 p-Iodoaniline 0. 12 0. 16 0. 1 1. 5 200 200 200 200 0. 15 p-Nitroaniline. 0. 3 0. 4 0. 1 3. 1 200 200 200 200 0. 005 m-Oarboxyaniline 0. 37 12. 5 0. 09 6. 2 200 200 200 200 0. 15 Hydroxyethylamine. 0. 18 3 0. 04 12. 5 200 200 200 200 Ephedrine 0. 15 1.2 0. 02 1. 5 200 100 100 200 0, 02 Phenethoxyarnine 0. 04 0. 4 0. 01 0. 5 200 200 200 200 0. l5 4-formylaminornethyl-4-pheny1- piperidine 1 8. 7 0. 24 25 200 100 200 0. 04

TABLEContinued Minimum inhibitory concentrations, 'ylml. Rifamyein B amide with M. aureus S. faec. S. haemol. B. aubtz'lis Proteus E. coli Klebs. Pszud H37RV pnemnon. aer.

4-benzyl-4-hydroxypiperidine 0. 08 0. 0. 04 5 200 100 100 200 0. fi-aminopenieillanie acid. 0. 5 3 0.6 6. 2 200 200 200 200 0.6 3-aminoxypropanol. 0. 75 5 0. 37 3. 1 200 200 200 200 0. 09 l-carbethoxypiperazine 0. 18 1. 5 0. 15 1. 5 200 100 100 200 0.09 Z-aminothiazole. 0.75 3. 1 0. 55 6. 2 200 200 200 200 0. 18 Aziridine 0. 18 1. 5 0. 18 1. 5 200 200 200 200 0. 18 Cyclopropylamine. 0. 18 1. 5 0. 0. 75 200 200 200 200 0. 09 2-aminoheptane 0. 15 0. 6 1 3. 1 200 200 200 200 0. 18 ter-Butylamine. 0. 15 1. 2 0.3 3. 1 200 200 200 200 0. 09 Propylarnine 0. 25 1. 2 0.3 3. 1 200 200 200 200 0. 18 4-aminobenzenelsulfonamide 0. 6 3 0. 3 25 200 200 200 200 0. 18 Dibenzylamine 0. 003 0. 03 0.015 0. 12 25 12. 5 25 25 0.37 Dipropylamine 0. 006 0. 06 0. 006 0.25 12. 5 6. 25 12. 5 0. 18 l-aminoethanol v 0. 075 0. 6 O. 045 6. 2 200 200 200 200 O. 09 Methylpropylamine" 0. 01 0. 04 0. 006 0. 18 25 12. 5 25 0. 18 Eth ylpropylamine 0. 0075 0. 05 0. 005 0. 37 25 6. 2 25 50 0. 09 N-methylcyclohexylamine. 0. 006 0. 025 0. 009 0. 18 12. 5 6. 2 25 25 0. 09 Diallylamine 0. 005 0. 05 0.003 0. 18 12. 5 6. 2 12. 5 50 0. 37 Methyl'butylamine 0. 003 07 05 0. 0025 0. 37 12. 5 6. 2 25 50 0. 37 N-ethylaniline 0. 003 0. 04 0. 006 0. 37 6. 2 6. 2 25 25 0. 18 N-methyl-benzylamine 0. 005 0. 07 0. 006 0. 37 12 5 12. 5 12. 5 50 0. 37 Di-isobutylamine. 0. 0012 0. 012 0.006 0. 045 6. 2 6. 2 25 25 0.3 Di-pentylamine... 0. 002 0.02 0. 025 0. 09' 6. 2 12. 5 12. 5 25 0.3 Ethyl-butylamine 0. 0015 0. 02 0. 006 0. 045 6. 2 6. 2 12. 5 50 0. 18 Methyl-propylarnine 0.002 0. 02 0. 006 0. 09 6. 2 6. 2 12. 5 50 0. 18 Methyl-ethylarnine. 0. 009 0.07 0. 009 0.75 12. 5 12. 5 25 50 0. 37 lVIetl1yl-ter-butylamine.. 0. 0025 0. 02 0. 004 0. 18 6. 2 6. 2 25 50. 0. 37 2,5-dihydroxymethylpyrrolidine. 0. 07 1. 3 0. 025 3. 1 100 100 100 100, 0. 18 N -cyclohexyl N -cyc1ohexy1an1inomethyl-N -methylpropylenediamine- 0. 009 0. 06 0. 009 0. 75 100 100 50 100 0. 15 Z-methylaminoethanol. 0. 1 1. 2 0. 06 5 100 100 100 100 0. 15 2,6-dimethylpiperidine 0. 003 0. O2 0. 005 0. 18 12. 5 6. 2 25 50 0. 15 N -methylaminoethyl-N ,N ,N

triethylethylenediamine 0. 03 0. 75 0. 09 0. 75 100 25 100 100 0. 18 4-methylarninophenoL O. 09 0. 0. 09 0. 18 100 100 100 100 0. 18 2-ethylaminoethanoL 0. 025 0. 55 0. 09 1. 5 100 100 100 100 0. 09 4-methylpiperidine 0. 005 0. 045 0. 01 0. 37 12. 5 6. 2 25 50 0. 37 2-methy1piperidine 0. 005 0. 03 0. 01 0. 18 25 6. 2 25 50 0. 18 Dibutylamine 0. 003 0. 03 0. 012 0. 06 12. 5 6. 2 25 50 0. 02 N ,N ,N triethylethylenediamine. 0. 12 0. 5 0. 03 3. 1 200 25 50 50 0. 075 2, 5-dica1'beth0xypyrrolidine 0. 005 0. 2 0. 012 0. 75 100 50 50 100 0. 37

A particular interest shows rifamycin B diethylamide (hereinafter named M-14) which proved extremely useful in preventing death in mice experimentally infected with Staphylococcus pyogenes var. aureus. The substance was given once a day for three consecutive days after infection with doses of the pathogenic organism corresponding to 20 and 200 times the LD The effective subcutaneous dose of M-14 in preventing death was 2.6 and 3.6 mg./kg. respectively, and the oral dose was 22.5 and 30.5 mg./ kg. respectively. The LD of M-14 in mice was 429 mg./kg. intravenously.

M'14 is best administered to humans in the form of ampuls containing 100-250 mg. of active substance. For instance, intramuscular ampuls are prepared from M-14, 250 mg.; ascorbic acid 25 mg.; K metabisulfite 3 mg.; NaHCO q.s. to pH 6; polyvinylpyrrolidone K17 300 mg.; distilled water q.s. to 3 ml. Alternatively, other examples of useful compositions are as follows:

250 mg. ampuls:

M-14 (sodium salt) mg 250 Ascorbic acid mg 25 Disodium EDTA mg 1 Lidocaine HCl mg 10 Na bisulfite mg 3 NaHCO q.s. to pH 6 Na methiolate mg 0.06 Distilled water q.s. to ml.. 3

150 mg. ampuls:

M-14 (sodium salt) mg 150 Ascorbic acid mg 25 Disodium EDTA mg 1 Na bisulfite mg 3 Na methiolate mg 0.06 NaHCO q.s. to pH 6.8 Distilled water q.s. to. u, 2 r n1 3 M-14 may be also administered by mouth in the form of tablets, prepared according to well-known procedures, containing 50-500 mg. of active substance.

In any case, the very low toxicity of M-14 allows safe administration to humans in daily oral doses of several grams, without any untoward effect. By parenteral route, doses of 1 g. daily and more can be reached safely for 10 days and longer.

The following non-limitative examples illustrate the invention.

EXAMPLE 1 EXAMPLE 2 Rifamycin B mon0ethylamide.Two grams of rifamycin B are suspended in m1. of anhydrous tetrahydrofuran. Then 0.550 g. of dicyclohexylcarbodiimide are added followed, after cooling at 5 C. by a solution of ethylamine in tetrahydrofuran. The solution is refluxed for 30 minutes, then it is concentrated to /s of its initial volume and allowed to stand for 3-4 hours at 4 C. The crystalline dicyclohexylurea separates out and is removed by filtration. The filtrate is poured into H O acidified with HCl at a temperature of 510 C., then extracted with benzene and the benzene solution is concentratedtoabout one half of its volume. 2030% of n-hexane is added and the mixture is again concentrated till practically complete crystallization occurs. By crystallization from benzene-n-hexane 1.4 g. of monoethylamide of rifamycin B are obtained.

Analysis.Calccl. for C41H56N2O13: C, H, N, 3.57. Found: C, 62.38; H, 7.33; N, 3.73.

EXAMPLE 3 Rifamycz'n B piperidide.-Five grams of rifamycin B are suspended in 200 ml. of anhydrous tetrahydrofuran. Then 1.375 g. of dicyclohexylcarbodiimide are added followed by 0.7 ml. of piperidide. The solution is refluxed for 2 hours, then concentrated whereby dicyclohexylurea separates as decribed in Example 2. The filtrate is poured into about times its volume of n-hexane, thus obtaining a precipitate of crude product which is collected and recrystallized from cyclohexane.

Analysis.-Calcd. for C H N O C, 64.06; H, 7.33; N, 3.40. Found: C, 63.03; H, 7.62; N, 3.68,

EXAMPLE 4 Rifamycin B pyrrolidide.Ten grams of rifamycin B are suspended in 250 ml. of anhydrous tetrahydrofur-an. Then 1.1 ml. of pyrrolidine are added followed by 2.75 g. of dicyclohexylcarbodiimide. The mixture is refluxed under stirring for 1.5 hours. The dicyclohexylurea is removed as described in Examples 2 and 3. The filtrate is then poured into water acidified with hydrochloric acid, the solution is repeatedly extracted with carbon tetrachloride, the organic phase is concentrated to small volume and 3-4 volumes of cyclohexane are added. The precipitate is recrystallized from cyclohexane.

Analysis.Calcd. for C H N O C, 63.68; H, 7.21; N, 3.45. Found: C, 63.63; H, 7.40; N, 303

EXAMPLE 5 Rifamycin B anilide.-Five grams of rifamycin B are suspended in 250 ml. of tetrahydrofuran together with 0.625 ml. of freshly distilled aniline and 1.375 g. of dicyclohexylcarhodiimide. The mixture is refluxed for 1.5 hours under stirring. The product is obtained as described in Example 3 and recrystallized from C01 Analysis.Calcd. for C H N O C, 64.89; H, 6.78; N, 3.36. Found: C, 63.79; H, 6.88; N, 3.33.

EXAMPLE 6 The amides of rifamycin B with the following amines were prepared according to the process described in the preceding examples:

Amine: Empirical formula Monomethylamine C H N O Monoisopropylamine C H N O Dimethylamine C41H55N2013 C43H0N2013 5-hydroxypentylamine C H N O Morpholine C43H58N2014 l-methylpiperaZine C44H61N3013 Dimethylazetidine C I-I N O 4-forrnyl-4-pheny1piperazine C H N O 4,4-dibutyl-pyrazolidine C H N O p-chloroallih lle C45H55N2O13C]. p-Bromoaniline C H N O Br p-Iodoaniline C H N O I p-NitrOaniline C45H55N3O15 m-Carboxyaniline C H N O Hydroxyethylamine C H N O Ephedrine C49H64N2O14 6 Amine: Empirical formula 4 'forrnylaminomethyl 4 phenilpiperidine C52H6'7N3014 4-benzyl-4-hydroxypiperidine C H N O 6-aminopenicillanic acid C H N O S 3-aminoxypropanol C H N O l-carbethoxypiperazine C H N O AZlflCliIl C4gH5 N2O13 Cyclopropylamine C H N O 'Z-aminoheptane C H N O ter-Butylamine C H N O Propylamine C42H53N2013 Dibenzylamine C H N O DiprOpylamine C45I'ig4N2013 l-aminoethanol C H N O 4aminobenzenesulpl1onamide C H N O S Methylpropylamine C H N O Ethylpropylamine C H N O N-methyl-cyclohexylamine C H N O Diallylamine C H N O is iethyl-butylarnine C H N O N-ethylaniline C H N O N-methylbenzylamine C H N O Di-isobutylamine C H N O Ethyl-butylamine C45H64N2O13 Methyl-propylamine C H N O Mfithyl-ethylamine C45'H53N2O13 Methyl-ter-butylamine C H N O 2,5-dihydroxymethylpyrrolidine C H N O N -cyclohexyl-N -cyclohexylarninomethyl N Methylpropylenediamine C55H84N4013 2-methylaminoethanol C., H N O 2,6-dimethylpiperidine C H N O N -methylaminoethyl-N ,N ,N

triethylethylenediamine C H N O 4-methylaminophenol C H N O Z-ethylaminoethanol C H N O 4-methylpiperidine C45H62N2O13 Z-methylpiperidine C45H62N2013 N ,N ,N -triethylethylenediamine C47H9N3013 Dibutylamine c47H N2013 Z-arninOthiaZole C42H53N3O13 Di-n-amylamine C H N O 2,S-dicarbethoxypyrrolidine C H N O We claim:

1. A process for preparing an amide of rifamycin B, which comprises heating and reacting rifamycin B with an excess over an equivalent amount of a compound selected from the group consisting of ammonia, and pri mary and secondary amines, in the presence of dicyclohexylcarbodiimide in tetrahyclrofuran.

2. A process as in claim 1, wherein rifarnycin B is reacted with ammonia.

3. A process as in claim 1, wherein rifamycin B is reacted with diethylamine.

4. A process as in claim I, wherein rifamycin B is reacted with ethylamine.

5. A rifamycin B amide selected from the class consisting of rifamycin B amide of ammonia, and primary and secondary amines.

6. Rifamycin B amide.

7. Rifamycin B diethylamide.

8. Rifamycin B ethylamide.

9. Rifamycin B piperidide.

l0. Rifamycin B pyrrolidide.

11. Rifamycin B anilide.

No references cited.

SAM ROSEN, Primary Examiner, 

5. A RIFAMYCIN B AMIDE SELECTED FROM THE CLASS CONSISTING OF RIFAMYCIN B AMIDE OF AMMONIA, AND PRIMARY AND SECONDARY AMINES. 